To be honest I think you need to bring it into a mechanic.

Precat O2 sensor contribute fuel/air mixture. Even though there is a code for O2 sensor there are several other components that contribute to air/fuel mixture that may be the core problem. Are you comfortable doing the troubleshooting?

I would suggest you to take the car to mechanic.

1. there is no such distributor cap. everything is electronically controlled by ignition coils. Have you ever worked on a car???? back in 80s?

2. bad O2 sensors usually don't trigger misfires on all cylinders.

3. posting specific code will help to diagnose

:iagree: Although I'm all in favor of people learning to fix their own car, but they should have some past experience or at least someone to help them along. If there's a BMW club in the area he should join them and see if someone can assist him. Giving advice to a noob that doesn't know anything about cars is just asking for trouble, can you say Lawsuit?

1. To be honest yes most of my experience under the hood is with cars that had caps. In the recent past I have not had the time or facility/tools to do any of my own work. I only recently have been able to do my own maintenance so I am going off of my liked experience.

2. That's fine if they don't, I need to check the spark plugs being the fact that I have 118000 miles on it. I'm just trying to troubleshoot. I didn't know if there was a central cool our something similar due to misfire on all cylinders not just a few.

3. I don't have the specific codes due to not writing them down. When I got them read I was in a hurry and was on a time line.

You probably have some sort vacuum leak. Check all the rubber boots & hoses, and also the rubber end caps.
Rubber boots is the easy one, the rubber hoses, you need to check them all. You have one that goes from the SAP on the right side of the engine, and around to the back. In the back of the engine there are 2 rubber caps/plugs. then on the left side of the engine you have a few more rubber hoses that control mainly your brake booster & fuel check valve (goes to the fuel filter - it's integrated). For these you could use a smoking machine, or a can of highly volatile chemical such as carb cleaner.

Another rubber cap/plug is on the CCV. But now you need to check the CCV system - those plastic hoses tend to crack as well. There are a few.

If everything checks OK, you have now 2 more things to check.
First is the DISA valve, which once it starts failing, can throw vacuum leak codes. How it's build, it has an integrated rubber O-ring, that has a raised lip on it. In time, this lip disintegrates, and your seal goes awol. Another shortcoming is the design per se. The flapper is driven by a plastic hex, not visible. That hex deteriorates in in time and allows for more and more play, so the flap doesn't open/close totally, but sometimes it will flutter very rapidly between these 2 positions, and you can hear that - it's what people refer to DISA whir. That flapping in turn will start dislodging the upper steel pin, and that one can get sucked into the engine leading to extensive damage. The DISA can be rebuild with the GAS kit if the rubber diaphragm is still OK (easy to test), or if not, then you need a new unit and you HAVE to get an original part. Aftermarket will not last, or will not work.

Then check the ICV because you're there. At the mileage you have, it's probably all gunked up, and could also lead to some erratic engine behavior. After you pull it, turn it back and forth and listen for a noise. If it's not present, then the valve is stuck, and you need to clean the unit by spraying solvent, letting it work, then let it dribble out. You need to repeat the procedure a few times, then start cleaning with Q tips soaked in solvent (contact cleaner, carb cleaner, etc). When installing back, look carefully, and you will see the ICV has an end tab on one side. That one is your guide and should be locked in place all the way up in the rubber grommet - not sure how to explain, but you will figure it out. Otherwise, it won't be sealed. So double check before threading the screws in, because the screws can go in with the ICV not seated properly.

Guys, give him a break. He's from Germany, and maybe some acronyms we use here are not used in Europe, and vice-versa.

good luck